Vertically adjustable drafting board table



JulyZl, 1953 E. LAxo r 2,646,322

VERTICALLY ADJUSTABLE DRAFTING BOARD TABLE Filed Jan. 10, 1949 3 Sheets-Sheet l INVEN TOR.

July 21,1953 E, Ago 2,646,322

VERTICALLY ADaIUSTABLE DRAFTING BOARD TABLE Filed Jan. 10, 1949 5 Sheets-Sheet 2 IN V EN TOR. v

Flas a. l

July 2l, 1953 E. LAXQ 2,646,322

VERTICALLY ADJUSTABLE DRAFTING VBOARD TABLE Filed Jian. 10, 1949 3 Sheets-Sheet 5 FIG. 6

Patented July 21, 1953 o UNITED STATES 'A P-.Lxielv'r OFFICE VERTICLIY'DJUSTABLEDRAFTING BOARD TABLE Ed Laxo, Oakland,-.Ca-lif. Application January 10, 1949; SerialNo. 70,089

4 claims. (c1. sii-soy l Y This iiiventionr relates to 'vertically' adljus'tabl draftingboard tables.

noV .the use or drafting board tables it is fro-f quently necessary to adjust the level or height of the board; for' example, it may be desirable to facilitate access to one part or another ofV the boardA or it may be necessary to adjust the board for draftsmen of different heights.'

'Y 'Such vertical adjustment 'should be simple to desired height, wherein `such adjustment can be quickly accomplished witha minimum of eo'rt and wherein, when suchA adjustment has been made, by the simpleoperation of releasing an operating member the board is automatically and instantly llocked atA the selected height.

- These andr other objects of the invention will be apparent from the ensuing description and appended claims.

in describing 'the invention reference win be had to the accompanying drawings, in which:

Fig'. 1l is a front elevation of the invention with the drawing board shown onlyiragmentarily.

Fig. 2 is a side elevation ofFig. l with af portion of one sidewall O'f the cabinet lbroken away to show the interior mechanism. Y

Fig. 3 is an enlarged inside view of the equalizing'neans for vertical adjustments, and compri-'ses a side View of the mechanism for -oneend of thecabin'et.Y

Figli is a rear View of the mechanism shown in Fig. Sand constitutes asideelevation of Fig. 3.

Fig.. 5` isan enlarged View of the braking or locking' mechanism for vertical adjust-Irrent's.l

Fig; 6V is a Vfragmentary `front,elevation-of the equali'zingbraking or locking, and spring' counterbalancingmeans. Y Y v f Fig. 7 is an enlarged fragmentary view showing the angular adjustment locking means.

Fig. 8 is an enlarged section taken on line 8 8 drawings and the like under the drawing board;

anda drawing' board t4 whichV is both, angularly ld 'vertically adjustable relative to vthe top wall Thefront' edge IiiA of' the drawing board overhangs Ithe'A frontV endV of theV cabinet suiciently to provide amplel'everage 'for adjusting the-angularity of the'board by Vpressing'vor lifting, and it thus: also providesV amplefoot clearance when working close to the board;

The automatic locking means for locking the board in any angularly 'adjusted position consists of a pair of vertically"=adjustable standards IB to each of which is xedly secured va quadrant II as indicated at yIliand I9 and having an arcuate slot Zilhavingifitsaxs coincident with the axis of V.the bolt I8, with the Vsupport members 2I of the `drawing board pivotally secured bythe bolts AIB for angular' adjustment the'reabout.V

- Abushing 22' is lixed in each of the members 2`I'with itsaxis'midway of' the* slot 2'0, and a shaft` -2'3 'is rotatable fin the respective bushings andmaintained against axialv movement by the set screws 2li engagingin the annularrecess 25 in the shaft', and each'endof the shaft 'terminates in acam 26 which clamps between the wallsof the slot ZUVWhe-n moved substantially cross-wise of the' slot.

vFixed on each end portion of the shaft '23' adjacent to -the'inside end of each bushing 232 is a lever 21 having one end' of a tension s'prngZ anchored therein with the other end of the spring anchored to the board as indicated at 2B', and af'cy'lindrieal barv 3,0 has its opposite ends anchoredpin, the hubs of the respective levers, "the bar being bentfto an elongated U-shape and extending forward to the front edge of the ldraw.- ing board forV convenient Vaccessibili-ty;*this bar functioningv as a release. vbar when raised manually andotherwise aiding the spring by its weight lin making the locking means effective'.

Thus, to angularly adjustthefboard, the bar 30 and the front edge ofthe board are simultaneously 'gripped andseither heavy Vpressure applied to tilt'the board up, or light pressure while la1lowing the board't'o lower,with the fingers releasing the release bar whenqthe proper adjustment is brackets 33 which are mounted on the frame of the cabinet.

Attached to each standard as indicated at 34 is a bracket 35 having a fixed arm 36 to one end of which is attached one end of a chain 3l as indicated at 33, with the other end of the chain attached to the bracket through a link 39 which is hinged at 49, the end of the chain being adjustable as to tension in this link as indicated at 4I, and this chain engages about an upper sprocket 42 and lower sprocket 43 which are respectively fixed on the upper and lower shafts 44 and 45, the upper shaft being ksupported by bearings 48, while the lower shaft is supported by bearings 41.

Mounted on the lower shaft 45 is a brake drum 48 having a V-groove 49 for the V-belt 50 one end of which is anchored to the frame I as indicated at l, with the other end anchored to-a lever 52 as indicated at 53; the lever being pivoted to a bracket 54 as indicated atl 55; the bracket be- -ing attached to one of the uprights 56 of the frame l0, and having a spring eye 5l in which one end of the tension spring 58 is anchored, the

other end of the spring being anchored in the arm 59 of the lever 52 as indicated at 69, and this arm terminating in a foot treadle 5 l.

The counterbalancing means consists of a torsion spring G2 one end of which is anchored to the shaft by a collar 63 with the other end anchored to the bearing 4T.

For elevating or lowering the drawing board, the treadle 6I is depressed, which releases the brake, the counterbalancs quite effectively supporting the board. With the foot treadle depressed the board is either forced down or lifted to the desired height, the sprockets and chains equalizing the movement at the respective ends ofthe board. When the desired elevation is attained, the foot treadle is released, the spring 58 'snaps the belt tight about the brake drum, securing the board in its instant vertically adjusted position. With the great length of torsion spring, the urgence toward lifting or to overcome the Weight of the board is quite constant with all degrees of adjustment.

Thus is provided a drawing board which is quickly and easily adjustable to any angle front to back and to any desired elevation, with all adjustments automatically locked upon release of the releasing means, and with no possibility of changing the board longitudinally from its relative level position because of the parallel operation of the standards controlled by the sprockets and chains.

I claim:

1. Equalizing means for vertically adjustable drawing board, comprising a frame; spaced standards vertically slidable in said frame for adjustable support of said drawing board; an upper and a lower sprocket for each standard and a shaft for the upper sprockets and a second shaft for the lower sprockets and supported by said frame; a bracket fixed on each standard; a chain for each standardand each having its respective ends fixed to the bracket and each including adjusting means for one end of the chain, with the chains passing about the respective upper and lower sprockets.

2. Equalizing and holding means for a vertically adjustable drawing board, comprising; a frame, a pair of spaced standards for support of the drawing board and vertically slidable in said frame; said equalizing means consisting of an upper shaft and a lower shaft supported by said frame and each having a sprocket at each end and a chain for each pair of upper and lower y sprockets, with the respective chains xed to Y ranged perpendicularly to the bars; chain and sprocket means including a first sprocket fixed to the shaft, a second rotatable sprocket, and a chain meshing with said sprockets and Xed to one of said bars for rotating the shaft when the bars and the drawing board are moved vertically, a brake for arresting rotation of the shaft; resilient means normally activating the brake to arrest such motion; and manually operable means for releasing the brake.

4. An adjustable drafting table comprising a drawing board; a stationary frame; spaced, parallel, vertical bars iixed to the board and slidably mounted on said frame for movement in a vertical plane to adjust the height of the board; a shaft rotatably mounted in the frame and arranged perpendicularly to the bars; chain and sprocket means for each bar, each said means including a rst sprocket xed to the shaft, a second rotatable sprocket and a chain meshing with said sprockets and fixed to one of said bars for rotating the shaft when the bars and the drawing board are moved vertically; a brake for arresting rotation of the shaft; resilient means normally activating the brake to arrest such rotation and manually operable means for releasing the brake; and counterbalancing means. for balancing the weight of the board and bars.

'Y ED LAXO.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 439,159 Jones et al Oct. 28, 1890 Y522,598 Jones July 10, 1894 689,707 Davis Dec. 24, 1901 1,165,144 Tillotson Dec. 2l, 1915 1,216,424 Edwards Feb.,20, 1917 1,483,051 Saunders Feb. 5, 1924 1,955,546 Froelich Apr. 24, 1934 2,312,636 Froelich Mar, 2, 1943 2,312,804 Derrick Mar` 2, 1943 2,356,924 Froelich Aug. 29, 1944 2,368,748 Doty Feb. 6, 1945 

